1. Field of the Disclosed Embodiments
The disclosed embodiments relate to emergency, night and alternative lighting configurations with the use of LEDs (light emitting diodes).
2. Description of the Related Art
Emergency lighting is a requirement for business or public space. Such lighting can be provided using, for example, typical “bug eye” head emergency light fixtures. An example is EL-STBE by the Exit Light Company, 1497 Poinsettia Ave, Suite 154, Vista, Calif., USA. However, such systems are heavy, unattractive, and require use-restricted or dedicated power circuits.
Alternatively, LED overhead lighting can be used as emergency lighting. Such would be obtained using, for example, drivers manufactured by Bodine, which is a division of Philips Electronics North America Corporation, located at P.O. Box 460, Collierville, Tenn., USA. As is known in the industry, an LED driver is a self-contained power supply that has outputs matched to the electrical characteristics of an LED fixture containing at least one LED. Drivers typically are current-regulated so as to deliver a consistent current over a range of load voltages. Drivers may also offer dimming by using pulse width modulation (PWM) circuits or current reducing, controlled by a number of known ways.
With the Bodine drivers, when normal power fails, the emergency drivers, which work in conjunction with an AC LED-driver, switches into “emergency” mode, operating the LEDs for a code-compliant 90 minutes. When AC power is restored, the battery powered drivers automatically return to the charging mode. For example, the Bodine BSL17C-C2 Emergency LED Driver, which is wired though a conduit, supports a lighting load up to 7 Watts (W) at a rated current of 270 milliamps (mA) maximum for a minimum of 90 minutes.
A limitation with this configuration is that the driver is required to operate by disengaging the primary power supply and running off an attached power supply for a duration of 90 minutes. Therefore, there is no ability to simultaneously operate both drivers and increase the intensity of the LED fixture as may be desired. There is also no ability to use this emergency driver to operate independently to provide night lighting. In addition, should any individual emergency power supply fail, the respective light would fail as well. Furthermore, when time comes to test or replace an individual emergency battery, extensive amount of work would be required to access the battery, which may be sealed behind a ceiling structure, such as drywall or sheetrock.
Dimming of an LED array in a fixture, so as to obtain a night light, as indicated, can be accomplished via a dimmer. However, there may be a decreased power factor due to the operation of the dimmer and loss in efficiency. The power factor loss results in a financial loss as well as efficiency losses due to the use of a high output power supply to supply a relatively small current.